The invention relates to a monolithically integrated push-pull driver. More particularly, the invention refers to a push-pull driver circuit which minimizes the noise generated by the driver switching on a commonly shared voltage supply line, e.g., ground line.
As a result of the progress made in the production of monolithically integrated semiconductor circuits, the circuits necessary for a data processing system can be increasingly miniaturized on the semiconductor chip. This permits producing a greater number of circuits in the same area, e.g., on a semiconductor chip. The higher integration density, however, leads to an increased number of chip output lines and thus to a greater number of driver circuits required. In the interest of fast data processing, the data handling has to be executed in parallel. This means that more and more driver circuits have to be switched simultaneously. However, the inductance of the package or conductor, by means of which the semiconductor chip is connected to the ground (potential) plane of the respective circuit card carrying the semiconductor chip, causes an increasing problem of noise generation on the chip ground line. As this noise could potentially affect adjacent storage elements serving to store the results of logical operations performed, the noise voltage must be kept below the switching threshold of the storage elements to prevent their state from being undesirably changed. As the magnitude of the noise voltage is, amongst others, dependent upon the number of simultaneously switching driver stages, this number must be limited to confine the noise voltage to a given minimum value. For this purpose it has been necessary to subdivide the total number of driver stages necessary for the particular data transfer situation into several groups of driver stages switching simultaneously in the respective group and to control the switching of the several groups in a time staggered fashion. However, this time-staggered switching results in reduced data transfer speed.
Accordingly, it is an object of the invention to provide an improved driver circuit of the above-mentioned type.
More specifically, it is an object of the invention to provide a push-pull driver circuit which allows to minimize the noise generated by the driver switching action.
It is a further object of the invention to provide a new push-pull driver with a reduced noise generation on a shared voltage supply line which is suitably adapted for use in applications where several drivers are switched simultaneously.